The invention concerns a method of producing a multilayer film and a multilayer film for covering a bone defect site.
Known films or membranes for covering bone defect sites are used, for example, in the field of jawbone or jaw augmentation in order to reconstruct a jawbone in the case of bone shrinkage or bone loss which can occur upon the extraction of a tooth or as a consequence of an inflammatory process around a natural tooth or an implant. Such films frequently have a shape structure of titanium which is arranged on a Teflon membrane and which is shaped over the bone defect site so that formed between the film and the bone defect site is a cavity in which bone material and in the case of natural teeth also the periodontium can subsequently grow. Fixing of the film is usually effected with bioresorbable or metal pins or screws which are fixed through the film to the jawbone. Alternatively, the film can also be glued to the base or to the jawbone. With implants which are introduced at the same time, the film can also be fixed to the implant head. As bone regeneration requires a number of months, a second operation is required after bone construction has occurred with a Teflon membrane in order to remove the film or Teflon membrane from the body again.
Cover layers of bioresorbable materials are also already known, which are dissolved by the body again by virtue of their bioresorbability, for example by hydrolysis. Such cover layers, however, generally suffer from excessively low stability in respect of shape in order to permit and maintain a structure for promoting bone healing during the duration of bone healing. The use of such a cover layer in conjunction with a shaping Teflon membrane again requires a second operation to remove the Teflon membrane from the body again.
The object of the invention is to avoid the above-described disadvantages and to provide a method which is improved over the state of the art of producing a multilayer film, as well as a multilayer film which is improved over the state of the art. In particular, the invention seeks to avoid a further operation for removal of the film.